/*
 * Copyright (c) 1999-2003, Carnegie Mellon University. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * 3. Products derived from the software may not be called "iVProg",
 *    nor may "iVProg" appear in their name, without prior written
 *    permission of Carnegie Mellon University.
 * 
 * 4. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes software developed by Carnegie Mellon University"
 */

package edu.cmu.cs.stage3.alice.core;

public abstract class ReferenceFrame extends Sandbox {

 // public static final ReferenceFrame ABSOLUTE = new World();
 // public ReferenceFrame() { }

 private static ReferenceFrame ABSOLUTE = null;
 public static void setReferenceFrame (World world) { ABSOLUTE = world; } // used: edu.cmu.cs.stage3.alice.authoringtool.JAlice.init()
 public static ReferenceFrame getReferenceFrame () { return ABSOLUTE; }

 public ReferenceFrame() { ABSOLUTE = this; }

 //Rem @Override
 protected void internalRelease (int pass) {
  super.internalRelease( pass );
  }

 }
